Fibrous product and method of making the same



Patented Jan. 14, 1936 FIBROUS PRODUCT AND METHOD or MAKING THE SAME George H. Ellis, St. Paul, Minn., assignor to The Insulite Company, Minneapolis,-Minn., a corporation of Minnesota No Drawing. Application February 5, 1934,

Serial No. 709,904

4 Claims. (01. 92-21) i This invention relates to a process for treating fibrous products such as products formed by felting which process is similar to those now utilized in the manufacture of fiber boards and the like, wherein the fiber is felted from a relatively diluted liquid suspension.

Another object of the invention is the production of fibrous products which have a pre-determined amount of toxic agent uniformly distributed therethrough.

Another object of the invention is incorporating of a toxic, inhibiting or repelling substance which can be easily and relatively inexpensively incorporated in the fiber product in relatively small amounts.

In the general practice of manufacturing fiber boards the fibers are suspended in water in the proportion of 1% parts of fiber to 98 /2 parts of water; the percentages may vary in the range of 4 parts of fiber to 96 parts of water.

The forming machine now in commercial use generally comprises a head box to which the fluid suspension having a fiber consistency of 1 to 4 per cent is discharged into the head box and from the head box fed to the forming machine on which the fibers are felted.

In the preparation of the fibrous material generally some vegetable substance is disintegrated into the fibrous state and is mixed with a liquid usually water, and is fed to'the head box by a suitable means, preferably a centrifugal pump.

Heretofore a great deal of difllculty has been experienced in mixing the toxic agent with the pulp and forming this pulp into a board without a great loss of this toxic agent. Such loss being commonly known as white water loss. According to my invention such loss is reduced to a minimum if not entirely done away with. I have found that it is possible to mix a coal tar product with the pulp and this is preferably done any time before the pulp reaches the head box. For instance an advantageous way of thoroughly commingling the coal tar product is by feeding such product into the suction side of the centrifugal pump which feeds the water having the pulp suspended therein to the head box. The action of the centrifugal pump thoroughly commingles the coal tar product through the pulp and when the sheet is formed from such pulp the coal tar product will be uniformly disseminated through the sheet.

It is highly desirable that the toxic agent be one that is not poisonous to human beings and the coal tar product falls within this class such products as creosote and creosote by products are examples of toxic agents that are nonpoisonous to human beings. I j

Itis to be understood that the invention is not limited to the use of a coal tar product and that any suitable metallic salts or any suitable organic compound may be used. One method that may be used includes mixing metallic compound (inhibiting material) with melted rosin and then pulverizing the mixture. agent thus prepared may be commingled with the pulp any time prior to forming the sheet. When the toxic agents are incorporated into the pulp in a manner heretofore described the loss in white water is reduced to a minimum.

Another means of incorporating the inhibiting material is to take one part of the toxic agent and mix with two parts of creosote or a suitable oil and agitate the toxic agent and the creosote or oil until thoroughly commingled, say for a period of approximately 15 minutes. Satisfactory results have been obtained by using vegetable oil as well as mineral oil. When this method of preparing the toxic agent is used there is likewise substantially no loss in the white water. I

It is preferred that the toxic agent of whatever type used be commingled with the pulp in a pre-determined quantity. This may be accomplished by placing the toxic agent, if in a dry state, in a suitable container and having a screw conveyer mounted in the bottom thereof. The amounts of toxic agent dispensed from this container depending upon the speed of rotation of such conveyer if the inhibiting agent is to be added in the liquid form the consistency of the agent is regulated by adding thereto a solvent, such as water. If the toxic agent is in a liquid form then a liquid dispensing meter is employed. Any suitable type of metering device may be used that will dispense a predetermined amount of toxic agent so that the amount of toxic agent incorporated in the finished sheet may be controlled.

It is preferred that the toxic agent be in jected into the pulp at the suction side of a centrifugal pump which is employed to force pulp in its water solution to the head box. The action of the centrifugal pulp thoroughly commingles the toxic-agent with the pulp so that when the sheet is formed it is substantially uniformly disseminated throughout the sheet.

The toxic and/or inhibiting agents may be used in any desired quantities but highly satisfactory results have been obtained by using 2 to 50 pounds per thousand square feet when The toxic .thereof.

What I claim is: 1. A fibrous mass derived from vegetable sources having distributed therethrough an insecticide and fungicide comprising a toxic agent that has been mixed with melted rosin and the rosin having the toxic agent therein reduced to a finely divided state.

2. The process of incorporating a toxic substance into fibrous products produced by felting fibers on a foraminous member from a diluted suspension 01' fiber in a liquid by mixing the toxic agent with melted rosin, reducing the rosin having the toxic agent therein into a finely divided state and commingling the rosin protected toxic agent in the diluted fibers prior to the formation of the fibrous products.

3. The process of rendering pulp products insect and fungi toxic, which comprises mixing a toxic agent with melted rosin, pulverizing the toxic agent and rosin, commingling the toxic agent and rosin with a diluted suspension of fibers in water by means of a pump, and forming a board-like body by felting fibers on a foraminous member.

' 4. The process of incorporating a predetermined quantity of toxic substance in a fibrous product produced by felting fibers on a foraminous member from a diluted suspension of fibers in water, by mixing-the toxic agent with melted 15 rosin, reducing the rosin having the toxic agent therein to a finely divided state, and commingling the rosin protected toxic age'nt with the diluted fibers by the action of a centrifugal pump, prior to the formation of the fibrous prod- 20 not.

GEORGE H. ELLIS. 

